1. Field of Invention
The present invention relates generally to the field of data transmission and more particularly to a method of post-detection selection space diversity for reducing the deleterious effects of fading and multi-path interference in wireless modems..
2. Discussion of Background
Wireless modems are used to interconnect computers or LANs using radio waves. Radio signals have advantages and disadvantages over hardwire systems. The wireless advantages include quick deployment, higher data rates than conventional telephone lines and the ability to serve customers independently of the traditional infrastructure.
The disadvantages of wireless transmission in the range of the MMDS/ITFS (multi-channel multi-point distribution system/instructional television fixed service) channels include the problem that the RF signal requires a line of sight path and strong mechanisms to decrease time lapse due to fading and multi-path.
The present inventors have realized that a space diversity system can be implemented in a wireless hub of a transmission system to reduce the disadvantages mentioned above and improve the performance of a wireless system. The present invention provides an optimized analysis of statistically independent diverse signals that increases the robustness and performance of a wireless hub.
The present invention is embodied as a method of space diversity for broadband wireless access, comprising the steps of, receiving spatially diverse signals, separately demodulating each of the spatially diverse signals, selecting a most correct of the demodulated signals, and forwarding the selected demodulated signal for further processing.
The present invention includes a space diversity device for a wireless hub, comprising, PHY layer equipment, including, a set of at least two antennas for receiving spatially diverse signals, a demodulator connected to each of said antennas, and each demodulator configured to demodulate signals received on the antenna connected to it, and MAC layer equipment comprising a selection mechanism configured to select a demodulated signal having a largest error free transmission.
Both the device and method may be conveniently implemented on a general purpose computer, or networked computers, and the results may be displayed on an output device connected to any of the general purpose, networked computers, or transmitted to a remote device for output or display.